The present invention relates to a gas burner of relatively low output, of the forced air and premixing type, comprising separate inlets for air introducing and combustible gas into a premixing chamber for discharge into a combustion chamber in which the premixture is ignited by means of a lighting electrode, the air and combustible gas inlets each comprising at least one flow control valve on the basis of all or nothing with the gas flow and progressive control on the air intake.
With a burner of this type, problems regulating the flow of air and combustible gas frequently arise as a result of fluctuations in pressure or losses of head due, for instance, to a partial obstruction or blockage of a filter mounted on the fan which supplies the burner with air. The feeding of incorrect quantities in the air:combustible gas ratio produces flame instabilities which seriously impair proper operation of the burner.